Re: [PATCH 1/1] mfd: Fix runtime warning caused by duplicate deviceregistration

From: Lee Jones
Date: Thu Jul 05 2012 - 08:41:11 EST


On 05/07/12 13:29, Mark Brown wrote:
On Thu, Jul 05, 2012 at 01:15:45PM +0100, Lee Jones wrote:
On 05/07/12 13:06, Mark Brown wrote:

You seemed to be suggesting that your fix was in some way related to the
DT changes in the MFD core. I'm unsure as to the relationship here.

How is it not related? In English the patch would say; "Only
register the AB8500 via the MFD API when we're booting with Device
Tree. This allows AB8500 related devices to be registered in the
normal way, rather than registering them individually using DT and
prevents duplicate registration when we are not executing a Device
Tree enabled boot."

This is what you said before and it still doesn't make much sense to me.
I'd expect that if anything your first statement would be the opposite
of what happens - it seems like your non-DT code is doing something
really odd. If anything I'd expect adding a DT to add duplicate
registrations, I'd not expect it to remove registrations.

What I'd expect is that if we can figure out that we need to register
the AB8500 automatically without any information from DT then we should
be able to figure out exactly the same thing in the non-DT case. I
would therefore expect that the change would instead be something which
removes the other source of registrations.

Now you're confusing me. :)

If DT is _not_ enabled, we do:

From platform code:
- Register the DB8500-PRCMU
- Register the AB8500

So you see the registration is separate.

If DT _is_ enabled, we do:

From Device Tree:
- Register the DB8500-PRCMU (which in turn registers the AB8500)

In this case we the DB8500-PRCMU goes on to register the AB8500 for us, so we need to ensure DT _is_ running before we go on to do that, because if we don't the DB8500-PRCMU will register it and so will platform code.

--
Lee Jones
Linaro ST-Ericsson Landing Team Lead
M: +44 77 88 633 515
Linaro.org â Open source software for ARM SoCs
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